1. Field of the Invention
The present invention relates to an audio disk, a device and method for reproducing audio data recorded thereon, and more particularly, to a disk on which high-quality audio data is recorded and a device and method for reproducing audio data recorded on the disk.
2. Description of the Related Art
Generally speaking, audio data recorded on a compact disk (CD) is sampled at 44.1 KHz, and each of the samples is audio data quantized by 16 bits. Such a CD is advantageous in usage and storage, as compared with a phonograph record (LP), while it has often been stated that the CD has a decreased sound quality. For instance, in the case that audio data sampled at 44.1 KHz and quantized by 16 bits is reproduced, it is difficult to reproduce the original sound and it may be deteriorated as compared with the disk used in the generation prior to CD. Actually, human beings' audible range may be over 20 KHz, and the dynamic range should be 120 dB. With the CD, it is impossible to record or reproduce audio data related to multi-channel music which has increasingly concentrated interest, because it can record only an audio signal of a maximum of two channels.
Coping with those problems, there have been suggested methods of improving the sound quality which is reproduced, by increasing the sampling frequency of the audio data and the number of recording channels.
Currently, one kind of disk reproducing device is designed to reproduce a variety of disks. One of those disks is a digital versatile disk (DVD). With the DVD, video and audio data is recorded at a high density, and the video data is recorded in the MPEG format. The audio data is recorded in the linear pulse code modulation (PCM), Dolby AC-3, or MPEG format. The device for reproducing the DVD video disk has a configuration of reproducing video/audio data so as to retrieve the video/audio data recorded on the DVD video disk.
In each of information areas of the DVD video disk, a video title set information management table (VTSI.sub.-- MAT) is recorded, and in the data areas sequential thereto, the audio/video data are recorded. The audio data recorded on the data areas of the DVD video disk have the structure of an audio pack. Here, first, the VTSI.sub.-- MAT and then the structure of the audio pack will be discussed.
As mentioned above, the DVD video disk has the VTSI.sub.-- MAT which contains information for reproducing video data and audio data. This is shown in the following tables 1a, 1b, 2a and 2b.
TABLE 1a __________________________________________________________________________ RBP Contents Number of Bytes __________________________________________________________________________ 0 to 11 VTS.sub.-- ID VTS Identifier l2 bytes 12 to 15 VTS.sub.-- EA END address of VTS 4 bytes 16 to 27 Reserved Reserved l2 bytes 28 to 31 VTSI.sub.-- EA End address of VTSI 4 bytes 32 to 33 VERN Version number of DVD 2 bytes Video Specification 34 to 37 VTS.sub.-- CAT VTS Category 4 bytes 38 to 127 Reserved Reserved 90 bytes 128 to 131 VTSI.sub.-- MAT.sub.-- EA End address of VTSI.sub.-- MAT 4 bytes __________________________________________________________________________
TABLE lb __________________________________________________________________________ 132 to 191 Reserved Reserved 6O bytes 192 to 195 VTSM.sub.-- VOBS.sub.-- SA Start address of VTSM.sub.-- VOBS 4 bytes 196 to 199 VTS.sub.-- VOBS.sub.-- SA Start address of VTSTT.sub.-- VOBS 4 bytes 200 to 203 VTS.sub.-- PTT.sub.-- SR.PPT.sub.-- SA Start address of VTS.sub.-- PTT.sub.-- SRPT 4 bytes 204 to 207 VTS.sub.-- PGCIT.sub.-- SA Start address of VTS.sub.-- PFCIT 4 bytes 208 to 211 VTSM.sub.-- PGCI.sub.-- UT.sub.-- SA Start address of VTSM.sub.-- PGCI.sub.-- UT 4 bytes 212 to 215 VTS.sub.-- TMAPT.sub.-- SA Start address of VTS.sub.-- TMAPT 4 bytes 216 to 219 VTSM.sub.-- C.sub.-- ADT.sub.-- SA Start address of VTSM.sub.-- C.sub.-- ADT 4 bytes 220 to 223 VTSM.sub.-- VOBU.sub.-- ADMAP.sub.-- SA Start address of VTSM.sub.-- VOBU.sub.-- ADMAP 4 bytes 224 to 227 VTS.sub.-- C.sub.-- AST.sub.-- SA Start address of VTS.sub.-- C.sub.-- ADT 4 bytes 228 to 231 VTS.sub.-- VOBU.sub.-- ADMAP.sub.-- SA Start address of VTS.sub.-- VOBU.sub.-- ADMAP 4 bytes __________________________________________________________________________
TABLE 2a __________________________________________________________________________ RBP Contents Number of Bytes __________________________________________________________________________ 232 to 255 Reserved Reserved 24 bytes 256 to 257 VTSM.sub.-- V.sub.-- ATR Video attribute of VTSM 2 bytes 258 to 259 VTSM.sub.-- AST.sub.-- Ns Number of Audio streams of VTSM 2 bytes 260 to 267 VTSM.sub.-- AST.sub.-- ATR Audio stream attribute of VTSM 8 bytes 268 to 323 Reserved Reserved 56 bytes 324 to 339 Reserved Reserved l6 bytes 340 to 341 VTSM.sub.-- SPST.sub.-- Ns Number of Sub-picture streams of 2 bytes VTSM 342 to 347 VTSM.sub.-- SPST.sub.-- ATR Sub-picture stream attribute of 6 bytes VTSM __________________________________________________________________________
TABLE 2b __________________________________________________________________________ 348 to 511 Reserved Reserved 164 bytes 512 to 513 VTS.sub.-- V.sub.-- ATR Video attribute of VTS 2 bytes 514 to 515 VTSM.sub.-- AST.sub.-- Ns Number of Audio streams of VTS 2 bytes 516 to 579 VTS.sub.-- AST.sub.-- ATRT Audio stream attribute table of VTS 6.4 bytes 580 to 595 Reserved Reserved 16 bytes 596 to 597 VTS.sub.-- SPST.sub.-- Ns Number of Sub-Picture streams of VTS 2 bytes 598 to 789 VTS.sub.-- SPST.sub.-- ATRT Sub-picture stream attribute table of l92 bytes 790 to 791 Reserved Reserved 2 bytes 792 to 983 VTS.sub.-- MU.sub.-- AST.sub.-- ATRT Multichannel Audio stream attribute table l92 bytes of VTS 984 to 1023 Reserved Reserved 40 bytes 1024 to 2047 Reserved Reserved 1024 bytes __________________________________________________________________________
In the VTSI.sub.-- MAT of tables 1a, 1b, 2a and 2b, VTSM.sub.-- AST.sub.-- ATR of RBP 260-267 indicates the audio stream attribute of VTSM.sub.-- VOBS, which is shown in FIG. 1. The respective fields' values become the internal information of the audio stream of VTSM.sub.-- VOBS. Referring to FIG. 1, the information of the audio coding mode recorded on b63-b61 is stored as in the following table 3.
TABLE 3 ______________________________________ b63-b61 Audio Coding Mode ______________________________________ 000b Dolby AC-3 010b MPEG-1 or MPEG-2 where no extension bit stream exists 011b MPEG-1 where extension bit stream exists 100b Linear PCM Audio others Reserved ______________________________________
In b55-b54, quantization/DRC information is stored as follows. If the audio coding mode is "000b", 11b is recorded. If the audio coding mode is 010b or 011b, the quantization information is defined as follows.
00b: the dynamic range control data is not present in the MPEG audio stream. PA1 01b: the dynamic range control data is present in the MPEG audio stream. PA1 10b: reserved PA1 11b: reserved
If the audio coding mode is 100b, the quantization information is stored as shown in table 4.
TABLE 4 ______________________________________ b55-b54 Quantization DRC ______________________________________ 00b 16 bits 01b 20 bits 10b 24 bits 11b Reserved ______________________________________
b53-b52, indicative of sampling frequency fs in FIG. 1, is shown in table 5.
TABLE 5 ______________________________________ b53-b52 fs ______________________________________ 00b 48 KHz 01b 96 KHz 10b Reserved 11b Reserved ______________________________________
b50-b28, indicative of the number of audio channels in FIG. 1, is shown in table 6.
TABLE 6 ______________________________________ b50-b28 Number of Audio Channels ______________________________________ 000b 1ch (mono) 001b 2ch (stereo) 010b 3ch (nultichannel) 011b 4ch (multichannel) 100b 5ch (multichannel) 101b 6ch (multichannel) 110b 7ch (multichannel) 111b 8ch (multichannel) others Reserved ______________________________________
In the VTSI.sub.-- MAT of the tables 1a, 1b, 2a and 2b, VTS.sub.-- AST.sub.-- ATRT of RBP 516-579 indicates the audio stream attribute of VTS, which is shown in FIG. 2. The respective fields' values become the internal information of the audio stream of VTSM.sub.-- VOBS. Referring to FIG. 2, the information of the audio coding mode recorded on b63-b61 is stored as in the following table 7.
TABLE 7 ______________________________________ b63-b61 Audio Coding Mode ______________________________________ 000b Dolby AC-3 010b MPEG-1 or MPEG-2 where no extension bit stream exists 011b MPEG-2 where extension bit stream exists 100b Linear PCM Audio 110b DTS (option) 111b SDDS (option) others Reserved ______________________________________
The multi-channel extension of b60 is an area which stores information indicative of whether the multi-channel extension is executed or not. If 0b is recorded, this means that the multi-channel extension is not selected. If 1b is recorded, this means that the multi-channel extension is performed according to the information of VTS.sub.-- MU.sub.-- AST.sub.-- ATRT recorded on RBP 792-983.
The audio type of b59-b58 is shown as in the following table 8.
TABLE 8 ______________________________________ b59-b59 Audio Type ______________________________________ 00b Not Specified 01b Language Included others Reserved ______________________________________
The audio application mode of b57-56 is shown in the following table 9.
TABLE 9 ______________________________________ b57-b56 Audio Application Mode ______________________________________ 00b Not Specified 01b Karaoke Mode 10b Surround Mode 11b Reserved ______________________________________
The quantization/DRC, sampling frequency fs, and the number of audio channels are shown in tables 4, 5, and 6, respectively.
In the VTSI.sub.-- MAT of tables 1a, 1b, 2a and 2b, the VTS.sub.-- MU.sub.-- AST.sub.-- ATRT of RBP 792-983 indicates the multi-channel audio stream attribute table of VTS, which is shown in FIGS. 3A and 3B. This VTS.sub.-- MU.sub.-- AST.sub.-- ATRT has two types, that is, VTS.sub.-- MU.sub.-- AST.sub.-- ATR (1) shown in FIG. 3A and VTS.sub.-- MU.sub.-- AST.sub.-- ATR (2) shown in FIG. 3B.
The DVD reproducing device analyzes the information written in the VTSI management table recorded on the DVD video disk, and reproduces the video/audio data written on the disk. Here, the audio data and video data written on the DVD video disk are made in units of packs. FIG. 4 shows the structure of a pack having no padding packet in the DVD. Referring to FIG. 4, one pack has a size of 2048 bytes, with 14 bytes of pack header and 2034 bytes of packet for video, audio, sub-picture, DSI or PCI. The packet header of 14 bytes contains 4 bytes of pack start code, 6 bytes of SCR, 3 bytes of program.sub.-- mux.sub.-- rate, and one byte of stuffing.sub.-- length.
FIGS. 5A-5E show the structure of an audio pack used in the DVD video. Specifically referring to FIG. 5A which depicts the structure of the linear PCM audio pack, it is made up of 14 bytes of pack header and 2034 bytes of linear audio packet. Here, the audio packet has one byte of packet header, one byte of sub.sub.-- stream.sub.-- id, 3 bytes of audio frame information, 3 bytes of audio data information, and one byte to 2013 bytes of linear PCM audio data.
FIG. 5B shows the structure of a Dolby AC-3 audio pack. Referring to FIG. 5B, the pack has 14 bytes of pack header and 2034 bytes of Dolby AC-3 audio packet. The audio packet has one byte of packet header, one byte of sub.sub.-- stream.sub.-- id, 3 bytes of audio frame information, and one byte to 2016 bytes of AC-3 audio data.
FIG. 5C shows the structure of an MPEG-1 audio or MPEG-2 audio pack having no extension bitstream. FIGS. 5D and 5E show the structure of an MPEG-2 audio pack having an extension stream. The audio packs shown in FIGS. 5A-5E have the same structure as in tables 10a and 10b, respectively, and private data areas corresponding to the respective formats separately.
TABLE l0a __________________________________________________________________________ Field Number of Bits Number of Bytes Value Comment __________________________________________________________________________ packet.sub.-- start.sub.-- code.sub.-- prefix 24 3 00 0001b stream.sub.-- id 8 1 1011 1101b private.sub.-- stream.sub.-- 1 PES.sub.-- packet.sub.-- length 16 2 `10` 2 3 10b PES.sub.-- scrambling.sub.-- control 2 00b not scrambled PES.sub.-- priority 1 0 no priority data.sub.-- alignment.sub.-- indicator 1 0 not defined by discriptor copyright 1 0 not defined by discriptor original.sub.-- or.sub.-- copy 1 1 or 0 origina:1, copy:0 PTS.sub.-- DTS.sub.-- flags 2 10b or 00b ESCR.sub.-- flag 1 0 no ESCR field ES.sub.-- rate.sub.-- flag 1 0 no ES rate field DSM.sub.-- trick.sub.-- mode.sub.-- flag 1 0 no trick mode field additional.sub.-- copy.sub.-- info.sub.-- flag 1 0 no copy info field PES.sub.-- CRC.sub.-- flag 1 0 no CRC field PES.sub.-- extension.sub.-- flag 1 0 or 1 PES.sub.-- header.sub.-- data.sub.-- length 8 0 to 15 __________________________________________________________________________
TABLE 10b __________________________________________________________________________ `0010` 4 5 provider defined Note 1 PTS[32 . . . 30] 3 marker.sub.-- bit 1 PTS[29 . . . 15] 15 marker.sub.-- bit PTS[14 . . . 0] 15 marker.sub.-- bit 1 PES.sub.-- private.sub.-- data.sub.-- flag 1 1 0 Note 2 pack.sub.-- header.sub.-- field.sub.-- flag 1 0 program.sub.-- packet.sub.-- sequence.sub.-- counter.sub.-- flag 1 0 P.sub.-- STD.sub.-- buffer.sub.-- flag 1 1 Reserved 3 lllb PES.sub.-- extension.sub.-- flag.sub.-- 2 1 0 `01` 2 2 0lb Note 2 P.sub.-- STD.sub.-- buffer.sub.-- scale 1 1 P.sub.-- STD.sub.-- buffer.sub.-- size 13 58 stuffing.sub.-- byte -- 0-7 __________________________________________________________________________ Note 1 and Note 2 are expressed as follows in tables 10a and 10b. Note 1: PTS[32 . . . 0] is put into every audio packet containing the first sample of the audio frame. Note 2: This value is contained only in the first audio packet of each VOB, but not in the succeeding audio packets.
In the audio packet of the linear PCM data having the structure of FIG. 5A, the data written in the individual data areas other than the common data shown in tables 10a and 10b is indicated as in the table 11.
TABLE 11 __________________________________________________________________________ Field Number of Bits Number of Bytes Value Comment __________________________________________________________________________ sub.sub.-- stream.sub.-- id 8 1 10100***b Note 1 number.sub.-- of.sub.-- frame.sub.-- headers 8 3 Provider Defined Note 2 first.sub.-- access.sub.-- unit.sub.-- pointer 16 Provider Defined Note 3 audio.sub.-- emphasis.sub.-- flag 1 3 Provider Defined Note 4 audio.sub.-- mute.sub.-- flag 1 Provider Defined Note 5 reserved 1 0 audio.sub.-- frame.sub.-- number 5 Provider Defined Note 6 Quantization.sub.-- word.sub.-- length 2 Provider Defined Note 7 Audio.sub.-- sampling.sub.-- frequency 2 Provider Defined Note 8 Reserved 1 0 number.sub.-- of.sub.-- audio.sub.-- channels 3 Provider Defined Note 9 Dynamic.sub.-- range.sub.-- control 8 Provider Defined Note 10 Audio Date Area (Linear PCM) __________________________________________________________________________ In table 11, Note 1-Note 10 are as follows. Note 1:*** indicates the decoding audio data stream number. Note 2: "number.sub.-- of.sub.-- frame headers" indicates the number of audio frames containing the first byte in the corresponding audio packet. Note 3: The access unit is an audio frame. The first.sub.-- access.sub.-- unit indicates the first audio frame containing the first byte in the corresponding audio packet. Note 4: "audio.sub.-- emphasis.sub.-- flag" indicates the state of emphasis. If the audio.sub.-- sampling.sub.-- frequency is 96KHz, "emphasis off" is recorded in this area. The emphasis is applied from the sample of the first access unit. 0b: emphasis off 1b: emphasis on Note 5: "audio mute flag" indicates the state of mute if all the data within the audio frame is zero. Mute is applied from the first sample of the first access unit. 0b: mute off 1b: mute on Note 6: "audio frame number" is the number within the group of audio frames (GOF) of the first access unit of the audio packet. This number includes "0" to "19". Note 7: "quantization.sub.-- word.sub.-- length" is the number of bits used in the quantization of the audio sample. 00b: 16 bits 01b: 20 bits 10b: 24 bits 11b: reserved Note 8: "audio.sub.-- sampling.sub.-- frequency" is the sampling frequency used in the sampling of the audio sample. 00b: 48 KHz 01b: 96 KHz others: reserved Note 9: "number.sub.-- of.sub.-- channels" indicates the number of audio channels. 000b: 1ch (mono) 001b: 2ch (stereo) 010b: 3ch (multi-channel) 011b: 4ch (multi-channe1) 100b: 5ch (multi-channel) 101b: 6ch (multi-channel) 110b: 7ch (multi-channel) 111b: 8ch (multi-channel) Note 10: "dynamic range control" indicates the dynamic range control word for compressing the dynamic range from the first access unit.
The stream id in the audio packets shown in FIGS. 5A-5E is determined as follows. First of all, the stream id of the linear PCM audio packet becomes 1011 1101b (private.sub.-- stream.sub.-- 1), its sub.sub.-- stream.sub.-- id being 1010 0***b. Second, the stream id of the AC-3 audio packet becomes 1011 1101b (private.sub.-- stream.sub.-- 1), its sub.sub.-- stream.sub.-- id being 1000 0***b. Third, the stream id of the MPEG audio packet becomes 1100 0***b or 1101 0***b, having no sub.sub.-- stream.sub.-- id. In the stream id or sub.sub.-- stream.sub.-- id, "***" indicates the decoding audio stream number having a value between 0 and 7. The decoding audio stream number is not allocated with the same number, regardless of the audio compression mode.
FIG. 6 is a diagram for explaining the structure of an audio pack and the audio stream. The audio data used in the DVD can be linear PCM data, Dolby AC-3 data, or MPEG audio data. Such audio stream is divided into a plurality of audio packs, as shown in FIG. 6. These audio packs are controlled in units of 2048 bytes. Here, the coding format of the linear PCM audio data is as shown in table 12.
TABLE 12 ______________________________________ Sampling frequency (fs) 48 KHz 96 KHz Sampling Phase Shall be simultaneous for all channels in a stream Quantization over 16 bits, 2's complementary code Emphasis applied (zero point: 50 .mu.s, not applied pole: 15 .mu.s) ______________________________________
In Table 12, the linear PCM audio stream data is made up with adjacent GOFs, each GOF having 20 audio frames except the final GOF. The final GOF is made to be equal to or smaller than 20 audio frames.
FIG. 7 shows the structure of an audio frame. Referring to FIG. 7, one audio frame has sample data in accordance with 1/600 seconds. If the sampling frequency fs=48 KHz, one audio frame contains 80 audio sample data. If the sampling frequency fs=96 KHz, one audio frame contains 160 audio sample data. One GOF coincides with 1/30 seconds.
FIGS. 8A-8C show sample data alignments for linear PCM. The sample data includes pieces of the respective channel data sampled at the same time. The size of the sample data varies with the audio stream attribute, each sample data being arranged continuously. FIGS. 8A, 8B and 8C show two formats of sample data at the respective modes. Here, FIG. 8A shows the alignment of sample data of a 16-bit mode. FIG. 8B shows the alignment of sample data of a 20-bit mode. FIG. 8C shows the alignment of sample data of a 24-bit mode.
The structure of the packet data of the linear PCM audio is shown in table 13.
TABLE 13 __________________________________________________________________________ Stream Mode Data in a packet Number Quanti- Maximum number Packet stuffing of Padding packet of zation of samples in a size first/other PES for first/other Channels fs(KHz) (bits) packet packet (byte) PES packet (byte) __________________________________________________________________________ 1(mono) 48/96 16 1004 2008 2/5 0/0 20 0/3 0/0 24 0/3 0/0 2(stereo) 48196 16 2/5 0/0 20 0/3 0/0 24 6/0 0/9 3 16 48/96 6/0 0/9 20 0/3 0/0 2448 0/0 12/15 4 16 48/96 0/0 10/13 2048 0/0 10/13 2448 0/0 18/21 5 168 0/0 10/13 2048 0/3 10/13 2448 0/3 0/0 6 168 0/0 18/21 2048 0/3 0/0 7 168 0/0 22/25 8 168 0/0 26/29 __________________________________________________________________________
If the number of samples is smaller than the values of table 13, the length of the padding packet increases to control the pack size. The samples are assigned to the packet boundary. In other words, the sample data of all the audio packets for the linear PCM audio always start with the first byte of S.sub.2n, as shown in table 13.
Explaining the channel assignment of the linear PCM, ACHO and ACHI channels correspond to L channel and R channel in the stereo mode, respectively. The multi-channel mode is coded to be compatible with the stereo mode.
As the audio option of the DVD, there is a digital theater system (DTS). The audio pack of the DTS has the pack header and audio packets, as shown in FIG. 9. The audio pack is aligned to the boundary between LBs within the audio frame units. Referring to FIG. 9, one audio pack includes 14 bytes of pack header and 2021 bytes of DTS audio packet. The DTS audio packet has one byte of packet header, one byte of sub.sub.-- stream.sub.-- id, 3 bytes of audio frame information, and one byte to 2016 bytes of DTS audio data. The stream id of the DTS audio packet is 1011 1101b (private.sub.-- 1), its sub.sub.-- stream.sub.-- id being 1000 1***b. Here, *** of the sub.sub.-- stream.sub.-- id indicates the decoding audio stream number having a value of 0 to 7. The decoding audio stream numbers are not assigned with the same number, regardless of the audio compression mode.
The structure of the DTS audio packet is shown in table 10, the private data area being in table 14.
TABLE 14 ______________________________________ Num- Num- ber of ber of Com- Field Bits Bytes Value ment ______________________________________ sub.sub.-- stream.sub.-- id 8 1 1000 1***b Note 1 number.sub.-- of.sub.-- frame.sub.-- headers 8 Note 2der defined First-access.sub.-- unit.sub.-- pointer 16 2 Note 3 provider defined DTS audio data area ______________________________________ In table 14, Note 1-Note 3 are shown in the fo11owing. Note 1: "***" indicates the decoding audio stream number. Note 2: "number.sub.-- of.sub.-- frame.sub.-- headers" indicates the audi frame number where the first byte exists in the DTS audio packet. Note 3: The access unit is an audio frame. The first access unit is the audio frame having the first byte within the corresponding audio packet, defined as the PTS of the audio pack. "first.sub.-- access.sub.-- unit.sub.-- pointer" indicates the first byte address of the first access unit with RBN from the final byte of the information area. If the first byte of the first access unit does not exist, 0000 0000h is recorded.
The DTS is provided with the DTS standards for the multi-channel sound of high quality. The DTS standards are shown in table 15.
TABLE 15 ______________________________________ Bit Rate mono(1ch) 64k to 384k bps 96k to 769k bpstereo(2ch) 256k to 1536k bps channel Sampling Frequency 48 KHz Only Audio Coding Mode 1/0, 2/0, 3/0, 2/1, 2/2, 3/2, *1 Protection CRC disabled Multilingual Channels 0 ______________________________________ In table 15, *1 is useful to the low frequency effects channels in the respective audio modes. The DTS audio having such a packet structure can be defined as the multichannel sound of high quality.
The number of channels available of linear PCM in the DVD video is shown in FIG. 10. In FIG. 10, of maximum bit rate is 6.75 Mbps, and the number of channels is determined as in table 16.
TABLE 16 ______________________________________ Sampling Frequency Number of Quantization Bits Number of Channels ______________________________________ 48 KHz 16 bit 8 channel 20 bit 6 channel 24 bit 5 channel 96 KHz 4 channel 3 channel 2 channel ______________________________________
The audio data recorded on the DVD video disk has a far better sound quality than that on the CD audio disk. The audio data recorded on the DVD disk has a sampling frequency, and the number of quantization bits and the number of channels greater than those on the CD audio disk. Therefore, the DVD reproducing device can reproduce high sound quality of audio data with multiple channels.
The DVD video disk enables a maximum of 10.08 Mbps of data transmission. With reference to this, it is noted that data sampled at 192 KHz can be reproduced with two channels. These values approximate the maximum sampling frequency designated as the requirements necessary in the next-generation audio in the advanced digital audio conference held in April, 1996 in Japan. If the pure audio data is recorded on the DVD disk, and the DVD reproducing device plays back the DVD audio disk, a better sound quality of the audio signal is obtained.